Many heated vessels are employed in industry. Typical of such vessels are chemical reactors, electrostatic precipitators and the like. Such vessels are either themselves heated or contain materials which have been heated or which generate heat. If such a vessel must be heated, fuels such as oil, natural gas, coal and the like must be burned to supply the energy needed to heat this vessel. In the past, when fuels were far less expensive than currently, insulation of such vessels to retain heat supplied to the vessel was not necessary. However, with the ever increasing fuel costs of today, and with the need to conserve fuel, it has become increasingly important to retain as much heat as possible within the vessel.
Even where such vessels need not be heated, such as in reaction vessels containing exothermic reactions and the like, increased emphasis on safety for plant employees dictates that insulation of these hot vessels be employed.
Thus, for whatever the economic or social reason, it has become increasingly popular, and it is sometimes necessary, to insulate heated vessels. Numerous insulation panels have been developed to meet this need. Most of these panels have in common an outer surface panel, an insulation material and a means for fixing the panel structure to the walls of the vessel.
A problem which is common to the known insulating panel structures for these purposes is the large amount of heat loss which occurs through the panels. This heat loss results from convection and radiation due to the normal high temperatures of the vessel walls which is transmitted from the vessel walls, through the panels and into the outside air. The metal panels their metallic fastening structures act as heat sinks to transmit this heat to the outside air. These heat sinks commonly arise at attachment points between the panels and the vessel walls and occur wherever the vessel walls and the insulation panels come into heat transfer contact. The more surface area of the panels or their supporting structure which contacts the vessel walls, the greater the heat loss. Such heat loss results in reduced insulation efficiency for the panels and an increased surface temperature of the panels as they cover the vessel, which may exceed permissable temperature levels for the health and safety of factory workers, as well as exceeding permissable heat loss values for the purpose of the vessel.
It is desirable, therefore, to produce a panel for insulating structures such as electrostatic precipitators, chemical reactors and the like which reduces substantially heat losses due to convection and radiation through heat sinks and thus increases the insulation efficiency of the panel and reduces the surface temperature of the panel.